Heat exchanger with baffle structure



June 20, 1967 BOSQUAlN ET AL 3,326,280

HEAT EXCHANGER WITH BAFFLE STRUCTURE 2 Sheets-Sheet 1 Filed Nov. 12, 1963 Fig. 2

June 20, 1967 BOSQUAlN ET AL HEAT EXCHANGER WITH BAFFLE STRUCTURE 2 Sheets-Sheet 2 Filed Nov. 12, 1965 United States Patent 0 3,326,280 HEAT EXCHANGER WITH RAFFLE STRUCTURE Maurice Bosquain and Maurice Grenier, Paris, France, assignors to LAir Liquide, Societe Anonyme pour lEtude et lExploitation des Procedes Georges Claude Filed Nov. 12, 1963, Ser. No. 322,650 Claims priority, application France, Nov. 22, 1962, 916,301, Patent 1,349,289 4 Claims. (Cl. 165-161) The present invention concerns a new form of heat exchanger having a tube bundle with its axis substantially horizontal, contained in an outer shell whose purpose is to ensure the warming up and vaporization of a liquid of a gas-liquid mixture flowing around the tubes of the bundle, in counter-current to at least one gas circulating in the tubes undergoing cooling and condensation.

A heat exchanger, allowing the warming up and vaporization of a gas-liquid mixture by indirect exchange with a gaseous mixture undergoing condensation, has already been proposed in US. Patent No. 2,900,799. 'In this exchanger the liquid to be warmed up and vaporized is introduced from above into the tubes of a tubular bundle, and flows down the inside of these tubes by gravity, the vapour produced going up axially of the tubes in counter-current to the liquid undergoing vaporization.

Such an arrangement is not however possible when it is required that the liquid formed by the partial condensation of the gas, on one hand, and the gas formed by the partial vaporization of the liquid, on the other, be removed with the residual gas and liquid respectively. In these conditions it is not possible to ensure the counterflow of the two fluids.

Further, it is desirable in the frequent cases where the pressure of the fluid which is exchanging heat with the gas-liquid mixture undergoing vaporization and warming up is relatively high, to pass this fluid through the interior of the tubes of the bundle in order to benefit from the better pressure resistance of these latter; the mixture to be warmed up and vaporized then passes around the tubes of the bundle. But hitherto no device has been known which would satisfactorily ensure an intimate contact between the gas and liquid phases throughout the vaporization of this latter.

The present invention allows these difficulties to be overcome and ensures very efiicient heat exchange between the gas to be cooled and condensed and the liquid to be warmed up and vaporized by means of a simple, easily constructed, low-cost device for the flow of this liquid.

According to this invention the heat exchanger is characterized in that it is constituted by an assembly in series of at least two elements each comprising:

(a) An internal envelope arranged around the tubular bundle, having in its lower section means of inlet of the mixture into the interior space of the envelope and in its upper section means of outlet of this mixture;

(b) Sloping gutters arranged between the outer shell and the inner envelope, of negative slope in the direction of the flow of the mixture, dividing the element int-o an inlet zone connected only to the means of inlet in to the interior of the inner envelope, and an outlet zone connected only to the means of outlet from this envelope;

(0) A vertical partition separating the element from the following one, and fitted with openings connecting the outlet zone of one element with the inlet zone of the following element.

A heat exchanger according to the principle of the invention is described below by way of example and with reference to the attached drawing; it allows in particular re-vaporiz'ation after separation of hydrocarbon fractions "ice condensed during the liquefaction of natural gas by the process which is disclosed and claimed in US. patent application Ser. No. 196,986 of May 23, 1962, now Patent No. 3,218,816, assigned to the same assignee as the as the present application.

FIG. 1 in the drawing shows an element of the heat exchanger in perspective, with the shell partly cut away.

FIG. 2 shows a cross section of the element in FIG. 1 in the plane XY perpendicular to the axis of the exchanger.

FIG. 3 shows a section along an axial plane of a heat exchanger comprising four elements such as that of FIG. 1 with the tubes omitted.

The heat exchanger element of FIGS. 1 & 2 has an internal bundle of tubes 2 and an inner prismatic envelope 3 comprising two symmetrical half shells each consisting of an upper inclined sheet 4, a vertical lateral sheet 5, and an inclined lower sheet 6. Between these two half sheets is a longitudinal opening 10 for the inlet of the gas and liquid mixture around the tubular bundle and another opening 11, for the outlet of this mixture, as indicated by the arrows. In addition sloping gutters 8 constituted by inclined sheets 7 welded to the external casing 1 and to the vertical lateral sheets 5 of the inner envelope, and vertical sheets 12 welded to the outer casing 1 along its generators, divide the element into an inlet zone connected only to the openings 10, for the inlet of the mixture into the interior of the inner envelope, and an outlet zone connected only to the openings 11 for the outlet of this mixture. The element is separated from the following one by a partition 9 fitted with openings 13 allowing access of the mixture from the outlet of one element to inlet of the following element.

The fiow of the mixture of gas and liquid in the element is clearly indicated by the arrows. The mixture penetrated through the lower openings 10 into the interior of the inner envelope, rises inside this around the tubes of the bundle, then over flows by the opening 11 and runs down the gutters 8 by gravity. It then passes through the openings 13 in the partition 9 into the bottom of the following element.

The heat exchanger 15 represented in FIG. 3 is constituted by four elements 16, 17, 18 and 19 analogous to that in FIGS. 1 and 2, separated by partitions 20, 21 and 22. The gas to be condensed under pressure enters the exchanger by the neck 23; it then passes into the tubular bundle fixed between the circular plates 27 and 28, and then leaves by the neck 25.

The mixture of vapour and liquid to be warmed up and vaporized comes into the first element 16 of the exchanger by the neck 29, flows successively through the four elements as indicated above, directed in particular by the sloping gutters 7, and then leaves by the neck 30. The tubular bundle may be fitted with bafiies 31 in a known manner.

It will be understood that the structure of the heat exchanger which has just been disclosed may be modified to a certain extent without departing from the invention. In particular the cross section of the inner envelope may be a polygon of any form, provided that it is symmetrical with respect to a vertical axial plane; it may also be cylindrical. The means for the inlet and outlet of the gas and liquid mixture may be constituted by a series of openings of any shape, and not only by a single longitudinal opening. Similarly, several lateral gutters may be fitted per element on each side of the inner envelope instead of a single one.

What We claim is:

1. A heat exchanger comprising an outer shell, 1ongitudinally spaced partitions therein defining a series of heat exchange stages each comprising an outer shell, an

inner shell supported within the outer shell and spaced therefrom, a bundle of tubes mounted within the inner shell, said inner shell forming spaced inlet and outlet zones parallel to said bundle of tubes communicating the space between the shells with the inner shell, and conduit means communicating the outlet zone of one stage through the intervening partition to the inlet zone of the adjacent stage, wherein the conduit means comprises a sloping gutter secured between the shells.

2. A heat exchanger comprising an outer shell, longitudinally spaced partitions therein defining a series of heat exchange stages each comprising an outer shell, a bundle of tubes mounted in the shell, a pair of spaced Walls mounted in the shell between the shell and tubes, the edges of the walls being spaced from each other to define inlet and outlet zones, and a sloping gutter secured between each wall and shell communicating the outlet zone of one stage through the intervening partition to the inlet zone of the adjacent stage.

3. The heat exchanger according to claim 2 wherein said bundle of tubes is within said spaced walls.

4. A heat exchanger comprising a longitudinally extending hollow housing, first and second end walls at each end of said housing, a box extending between said end walls, said box having spaced side walls, a pair of liquid separating walls extending from said first end wall adjacent the top of said box to said second end wall adjacent the bottom of said box to form liquid compartment-s below said liquid separating walls and liquid compartments above said walls, said liquid separating walls extending outwardly from said spaced side walls, said liquid compartments being in flow communication with the interior of said box along the length thereof, said first end wall having an opening therein below said liquid separating walls on either outward side of said box side walls, said second end wall having openings therein above said liquid separating walls on either outward side of said box side walls, said second end wall openings extending upward to a point below the top edge of said box side walls.

References Cited UNITED STATES PATENTS 1,083,281 1/1914 Jefireys 16516l X 2,084,743 6/1937 Rathburn 165-414 2,091,757 8/1937 Hanny 165-111 3,197,387 7/1965 Lawrance 202--173 FOREIGN PATENTS 200,463 7/ 1923 Great Britain.

ROBERT A. OLEARY, Primary Examiner. A. W. DAVIS, Assistant Examiner. 

4. A HEAT EXCHANGER COMPRISING A LONGITUDINALLY EXTENDING HOLLOW HOUSING, FIRST AND SECOND END WALLS AT EACH END OF SAID HOUSING, A BOX EXTENDING BETWEEN SAID END WALLS, SAID BOX HAVING SPACED SIDE WALLS, A PAIR OF LIQUID SEPARATING WALLS EXTENDING FROM SAID FIRST END WALL ADJACENT THE TOP OF SAID BOX TO SAID SECOND END WALL ADJACENT THE BOTTOM OF SAID BOX TO FORM LIQUID COMPARTMENTS BELOW SAID LIQUID SEPARATING WALLS AND LIQUID COMPARTMENT ABOVE SAID WALLS, SAID LIQUID SEPARATING WALLS EXTENDING OUTWARDLY FROM SAID SPACED SIDE WALLS, SAID LIQUID COMPARTMENTS BEING IN FLOW COMMUNICATION WITH 